Office copying machine



Nov. 8, 1960 Filed June 3, 1957 3 Sheets-Sheet 1 INVENTOR.

K5711!" J/Mi gmwm BY g 2 ATTORNEX Nov. 8, 1960 K. J. MAGNUSSON OFFICECOPYING MACHINE 3 Sheets-Sheet 2 Filed June 3, 1957 SUP/Z) INVENTOR.1E1: cl Mgmzssozz ATTORNEY Nov. 8, 1960 K. J. MAGNUSSON 2,959,095

OFFICE COPYING MACHINE Filed June 3, 1957 3 Sheets-Sheet 3 IN V EN TOR.

ATIURNEX United States Patent OFFICE COPYING MACHINE Knut J. Magnusson,Princeton, N.J., assignor to Radio Corporation of America, a corporationof Delaware Filed June 3, 1957, Ser. N. 663,199

4 Claims. (Cl. 88-24) This invention relates to a copying machine, andmore particularly to an improved oifice copying machine, of compactstructure, for producing copies from subject sheets by an electrostaticprinting process.

An object of this invention is to provide an improved oflice copyingmachine, of very compact structure, for producing copies of standard orlegal size subject sheets.

A further object of this invention is to provide an oflice copyingmachine of compact structure having an extensible track for areciprocable subject holder.

A still further object of this invention is to provide an oflice copyingmachine having a rotary drum copy holder including novel means forpositioning and clamping a copy sheet in the drum.

A still further object of this invention is to provide an oflice copyingmachine having a rotary drum copy holder and a reciprocable subjectholder and including novel means for synchronizing the movements of thetwo holders.

An oflice copying machine, embodying the invention, may be contained ina rectangular housing. As viewed from the top, the dimensions of thehousing may be only slightly greater than the dimensions of the largestsheet to be copied. A rotary drum copy holder, mounted on a horizontalaxis, faces an opening in the front wall of the housing. A traversingsubject holder is mounted at the top of the housing to be reciprocatedfrom the front to the rear of the housing. The subject holder is coupledto the drum so that it is automatically advanced, in one direction, insynchronism with the drum. An optical system causes light reflected fromthe subject holder to be projected onto the surface of the drum. Thesubject holder is mounted in a cover, for the housing, which isextensible to lengthen the path for the traversing subject holder.

Means are provided on the drum for clamping a copy sheet, such as asheet treated so as to retain an electrostatic charge, to the drum andfor automatically controlling the depth of insertion of the sheet intothe clamping means. The clamping means may be controlled to select thedepth to which a sheet is inserted. Means are positioned adjacent theperiphery of the drum for providing a uniform electrostatic charge onthe surface of the treated sheet clamped to the drum, for applying anelectroscopic developer powder to the charged surface of the sheet, andfor fusing the developer powder held to the sheet by the electrostaticcharge.

The novel features of the invention, as well as additional objects andadvantages thereof, will be understood more fully from the followingdescription when read in connection with the accompanying drawings, inwhich:

Figure l is a perspective view of an oflice copying machine embodyingthe present invention;

Figure 2 is a perspective view, partially broken away, of the top of themachine of Figure 1 showing the subject holder and its supportingmechanism;

Figure 3 is a sectional view, in side elevation, of the machine ofFigure 1;

Patented Nov. 8, 1960 Figure 4 is a view, in front elevation, of therotary drum copy holder and associated mechanisms;

Figure 5 is a view, in end elevation, of the drive mech anism, takenalong the line 5-5 of Figure 4 as viewed in the direction of theappended arrows; and

Figures 6, 7, and 8 are fragmentary end views of the drum, taken alongthe line 66 of Figure 4 as viewed in the direction of the appendedarrows, illustrating the drum clamping mechanism.

The machine to be described, embodying the invention in illustrativeform, is particularly adapted for use with an electrostatic printingprocess. In a typical electrostatic printing process, a record, such asa paper sheet having a photoconductive insulating layer on one surface,is provided with a uniform electrostatic charge. The charged surface isexposed to a light image, which bleeds the charge from portions of thesurface, to form an electrostatic charge image. The light image may beformed from a photographic transparency or may be reflected from anopaque subject, for example. The charge image is made visible byapplying a colored electroscopic developer powder to the surface. Thepowder adheres to the charged areas of the surface and may then be fusedto the record to provide a permanent image.

Referring to Figures 1 and 2 of the drawing, a hous ing 11 for theoflice copying machine is rectangular in configuration. A cover 12encloses the top of the housing and is movable rearwardly to overhangthe housing 11. The cover 12 partially supports a reciprocable subjectholder 13. An opening 17, in the front of the housing, exposes a rotarydrum copy holder 15. A con trol panel 18 is mounted along one side ofthe open ing 17.

Referring to Figure 3 of the drawing, the essential elements of themachine are shown in a preferred arrangement. The subject holder 13 ismounted for reciprocating movement across the top of the housing 11,from front to rear. The supporting means for the subject holder 13, tobe described with reference to Figure 2, is not shown in Figure 3. Therotary drum copy holder 15 is mounted, for rotation about a fixed shaft16, adjacent the opening 17. The subject holder 13 is coupled to thedrum 15 by means of a cable 19 and is automatically advanced, insynchronism with the drum, through a mechanism to be described. Light,from a pair of lamps 21, is directed by elliptical reflectors 22 to asubject 20 supported in the subject holder 13. An optical system, forprojecting the light reflected from the subject 20, includes a lenssystem 23, a mirror 25, and an optical slit 27. The reflected image isinverted in the optical system. The optical system is enclosed by lightshields 29.

The subject 20, which may be a printed sheet or a photograph, forexample, is supported in the subject holder by means to be described.One end of a copy sheet 31 is clamped to the external, cylindricalsurface of the drum, by means to be described, and is carried around thedrum as the drum rotates. The drum rotates in a clockwise direction, asviewed in Figure 3.

A corona charging device 33 is mounted at a station adjacent theperiphery of the drum 15 beneath the drum. This device includes aplurality of spaced wires 35 which span the length of the drum and areenclosed in a shield 37 to direct the corona discharge toward the drumsurface. The wires 35 are connected to a power supply 39 which impressesa high potential on the wires 35 with respect to the drum 15. The coronadischarge from the wires 35 produces a uniform electrostatic charge onthe coated surface of the copy sheet 31, which is the surface of thesheet facing away from the drum surface. The light, reflected from thesubject, is projected onto thecopy sheet at an exposurestation adjacentthe charging device 33 in the direction of rotation of the drum.

Apparatus for depositing electroscopic developer powder is mounted at astation next adjacent the exposure station in the direction of rotationof the drum. The developer powder is mixed with magnetic carrierparticles to form arnagnetic developer mix 43 which is contained in atrough 45. The mixing of the developer and the magnetic particlesimparts a charge to thedeveloper particles which is of polarity oppositefrom the charge on'the'copy sheet. A rotary, magnetic member 47 isrotatably mounted in the trough 45 about an axis parallel to the axis ofrotation to the drum. The trough 45-and the member 47 span the length ofthe drum 15.

A magnetic pole piece 49 is mounted withinthe drum; adjacent thecylindrical surface of the drum, and'opposes the'rotary member 47. Thepole piece is supported by brackets 51 which are secured to the fixedshaft 16. The brackets 51 are permanently magnetized bars and thepole-piece 49 acts as an extension of the magnets 51; The magnetic fieldfrom the pole piece 49 passes through the drum wall and through theportion of the rotary member 47 nearest the drum. The rotarymemher 47rotates in a counter-clockwise direction, as viewed in Figure 2, andcarries the developer mix 43 from the bottom of the trough intoengagement with a copy sheet carried on the drum. The developer mixadheres to the rotary member 47 in the form of a brush or bristles. Inthe area of contact with the copy sheet, the magnetic fi'eld passingthrough the copy sheet is concentrated by the pole piece 49. This tendsto stiffen the brush or bristles at the point of contact with the paper.The

developer powder particles are attracted from the rotary member to thecopy sheet, while the magnetic particles are retained on the rotarymember. At the portion of the rotary member 47, farthest from the drum,the magnetic field is so weak that the mix falls from the rotary memberinto the trough. This provides for remixing of the mix particles. Areservoir 53, mounted over the trough 45, replenishes the supply ofdeveloper powder in the developer mix. The peripheral speed of thecylindrical member 47 is greater than that of the drum 15 to provide arelative motion between these members.

A fusing device 55 is mounted at a station next adjacent the developerapparatus 41 in the direction of rotation of the drum. The fusing devicemay comprise any suitable heating apparatus for softening either thedeveloper powder or the coating on the copy sheet to cause the developerpowder to permanently adhere to the sheet and thereby provide a fixedimage.

Referring now particularly to Figure 2, the cover 12 defines arectangular top portion for the housing 11 and encloses the subjectholder 13. The cover is supported by a pair of rods or tracks 63 whichextend from front torear of the housing, on either side. the cover 12,two brackets 65 and 67 extend downwardly and are provided with bearingsfor slidably engaging the rods 63. The brackets 65 are mounted adjacentthe front of the cover and the brackets 67 are mounted 'intermediate thefront and back of the cover. With this arrangement, the cover may bemoved rearwardly with respect to the housing so that a substantialportion of the cover overhangs the housing.

Asshown in Figures 2 and 3, the subject holder 13, which is supportedwithin the cover 12, includes a frame 69'supporting a transparent glassplate 71. A pressure plate-73 is secured to the rear of the frame 69 byresilient hinges 75. and to the front of the frame by a resilient latchmember 77. The pressure plate 73 may then be raised, with respect to theframe, for the purpose of inserting or removing the subject sheet 20.The pressure plate may have a resilient facing to assure uniform contactof'the sheet with the glass plate 71 when the pressure plate is latched.

Th'e's'ubje'ct holder is.supported, at.its front end, on

On each side of a pair of rods or tracks 79 which extend from front torear of the housing adjacent to the rods 63. Brackets 81, extendingdownwardly from the frame 69, are provided with bearings for slidablyengaging the rods 79. The subject holder is supported, at its rear end,on a pair of rods or tracks 83, which extend from front to rear of thecover 12 adjacent to and parallel to the rods 63 and 79. Brackets 85,extending laterally from the frame 69, are provided with bearings forslidably engaging the rods 83. The rods 79 and 83 provide a track forthe subject holder extending from the rear of the cover to the front ofthe housing.

A front portion 87 of the cover 12 is hinged so that it may be raisedout of the way to permit access to the subject holder and to' permitmovement of the subject holder relative to the cover. The cover portion87 includes a handle 89 for manually moving the cover with respect tothe housing 11. It will be seen that when the cover is moved to itsrearward limit, a track is provided for the subject'holder which issubstantially longer than the depth of the housing 11. When the machineis not in use, the cover is positioned directly over the housing andcompletely encloses the subject holder. The housing then presents aneat, closed appearance andthe office copier occupies a minimumof space.

Referring now to Figures 3, 4, and 5, the copyholder drum 15 and thedriving means for the drum and the subject holder 13 are shown indetail. The drum 15 is comprised of a cylindrical wall 91 supported'byend plates 93 and 94. The plates 93 and 94 are rotatably supported onthe fixed shaft 16. A pulley 97 is secured to the external face of theplate 94. The drum is driven by a motor 99 through abelt 101 whichcouples the pulley 97 to a motor pulley.

A cam 103, having a peripheral cam surface configuration as shown inFigure 5, is fixed to the-shaft 16 adjacent the pulley 97. A pulley 105,rotatablymounted on the shaft 16 adjacent the cam 103, has a workingdiameter identical to the outer diameter of the drum surface. Thesubject holder 13 is advanced by the pulley 105 through the cable 19.Referring particularly to Figure 3, the cable 19 passes over the pulley105 andidler pulleys 109, 111 and 113. The pulleys 109 and 111 define ahorizontal run, for the cable, adjacent thepath of the subject holder.The subject holder isse-' cured to the cable by means of a clamp member15 extending downwardly from the subject'holder frame 69.

the peripheral drum surface.

synchronized.

A pin 117, fixed to the pulley 105, extends toward the drum pulley 97.Latch means such'as a cam follower, in'the form of an L-shaped dog 119,is pivotally mounted, at one end, on the drum pulley 97; A'roller' 121is rotatably mountedionthe dog 119 for engagement with the surface ofthe cam 103. The cam surface is.

cylindrical with the exception of a: dip 123'provided. at one portion ofthe surface. Whenrthe. roller '12'11is rid-1 ing 'on the cylindricalportion of the cam surface, the: dog 119 is positioned to engage the pin117 whereby thefcable pulley 105 isdriven by the belt pulley 97.The'con-l figuration of the dog 119 is such that the load force;

exerted by the pin117'on the dog, urges. or'camsrthe dog against thecam'surface.

the limit of advance for the subject holder 13.

Referring now to Figures 4, 6, 7, and 8, a mechanism" for clamping acopy sheet to the drum will be described. An opening, parallel to theaxis-of rotation of the drum,

is formed in the' drumwall 91 by anoverlapping of theend portionsof'the' drum wall 91; The outer'end'of When thedog 119: rides; into thedip 123, thedog becomes disengagedfromtthe= pin 117. The cam is orientedso that the dip 123 defines:

the drum wall is rigidly positioned by the end plates 93 and 94. Theinner end of the drum wall is unsupported and may be deflected inwardly.The inner end of the wall is made of a resilient material which isbiased outwardly to engage the outer end in clamping relationship.

The inner end portion is formed in the shape of a channel 131 whichfaces the external end and extends across the drum. The channel 131 andthe external end define a substantially closed rectangular chamber, asviewed from an end of the drum.

A substantially rectangular bar 133, having dimensions smaller than thedimensions of the above mentioned rectangular chamber, is disposed inthe chamber and is rotatably supported in the end plates 93 and 94. Anarcuate lever 135 is fixed, at one end, to one end of the bar 133 andlies adjacent the outer face of the end plate 93. The lever 135 liesadjacent the periphery of the end plate 93 and is contoured tocorrespond with the contour of the plate periphery.

The normal position of the bar 133 and the lever 135 is shown in Figure6. In this position, the ends of the drum wall 191 are in clampingrelation and the bar lies relatively loosely in the chamber defined bythe channel 131. The lever 135 is aligned with the periphery of the endplate 93.

Referring now to Figures 7 and 8, it will be seen that if the bar 133 isrotated in either direction from its normal position, the chamber isexpanded and the internal end of the drum wall is deflected away fromthe external end. This, then, opens the drum wall to permit theinsertion or removal of a copy sheet. Referring to Figure 7, the bar 133is rotated in a clockwise direction. In this position, the edge of thebar, nearer the opening, defines a limit to which a copy sheet may beinserted. In this case, only a small margin of the copy sheet is clampedin the drum providing a maximum sheet area for the purpose of printing.Referring to Figure 8, the bar is rotated in a counter-clockwisedirection. In this position, a groove 137 in the bar, which is nowpositioned adjacent the outer end of the drum wall, defines a limit towhich a copy sheet may be inserted. In this case, a wider margin of thecopy sheet is clamped in the drum. The deep setting may be desirable,for example, for use with Multilith masters which have a relatively widemargin unavailable for printed matter.

The lever 135 is controlled by means of a control lever 139 which ispivotally mounted, intermediate its ends, on the machine frame (notshown) adjacent the end plate 93. The control lever 139 includes achannel portion 140 at one end, through which the arcuate lever 135passes as it is carried by the drum 15, and an operating finger 141 atthe other end. The operating finger extends outwardly from the front ofthe housing adjacent the control panel 18 (see Figure 1). In the indexposition of the drum, a substantially circular end portion 136 of thearcuate lever 135, opposite from the point of attachment of the bar 131,is positioned within the channel portion 140 of the control lever. Whenthe control lever is then manually rotated about its pivot point, in onedirection or the other, it, correspondingly, rotates the arcuate lever135 in one direction or the other to place the rectangular bar 133 inone or the other of the above described positions. A copy sheet may thenbe inserted into the drum. A guide member 143, which forms the lowerwall of the opening 17, is positioned to guide the copy sheet into thedrum opening.

In operation, the hinged portion 87 of the cover 12 is raised to permitmovement of the cover to its rearward limit as shown in Figure 2. Thisexposes the subject holder 13. The pressure plate 73, of the subjectholder, is then raised by releasing the latch member 77 so that asubject sheet 20 may be placed in the subject holder. The subject sheetis placed face down on the glass plate 71 with the top of the sheettoward the front of the sub- 6 ject holder. The subject holder is thenpushed back manually to its rearward limit, which is the start position.

The copy holder drum is in its index position, indicated in Figures 6,7, and 8, wherein the circular end of the lever is positioned within thechannel portion of the lever 139 and wherein the drum opening ispositioned adjacent the guide member 143. The control lever finger 141may then be deflected in either direction, to select the clamping depthfor a copy sheet 31, and the leading edge of the sheet is inserted inthe drum opening. The photoconductive surface of the sheet is positionedaway from the drum. The control finger 141 is then released, returningto its normal position as the copy sheet is clamped within the drumopening.

The machine is then operated by pressing a start button which causes themotor 99 to drive the drum through one revolution. The drum isautomatically stopped (by means not shown) when it returns to its indexposition. The drum carries the copy sheet, first, past the chargingstation where a uniform electrostatic charge is provided on the exposedsurface of the sheet. The electrostatic charge acts to hold the sheettightly to the drum so that it does not slip during subsequentoperations. The sheet is next carried to the exposure station. As theleading edge of the sheet approaches the exposure station, the dog 119,which is rotating with the drum, engages the pin 117 on the pulley 105.The subject holder 13 now begins to advance toward the front of themachine at a linear speed identical to the linear speed of the copysheet on the drum. Simultaneous with the beginning of advance of thesubject holder, the projection lamps 21 are energized. The lamps may becontrolled by microswitches actuated by a projection on the drum (notshown), for example, or by any other known means.

As the subject holder and the copy holder now continue to advancetogether, the subject sheet 20 is scanned by a slit of light from thelamps 21 and the light image reflected from the subject sheet isprojected onto the copy sheet through the lens system 23 and the opticalslit 27, which accurately defines the slit of light projected onto thecopy sheet. The optical system inverts the light image so that it isright-reading on the copy sheet. The electrostatic charge on the copysheet is bled off in proportion of the amount of light striking the copysheet. In this manner, a latent electrostatic charge image is formed onthe copy sheet which is identical to the subject sheet.

The copy sheet is next carried past the developer station where therotary member 47, which may also be driven by the motor 99, carries thedeveloper mix 43 into engagement with the copy sheet. The developerpowder, having a charge oposite to that of the copy sheet, is attractedfrom the developer mix to the copy sheet in proportion to the charge nowexisting on the copy sheet. The developer powder is colored so that thelatent electrostatic charge image now becomes a visible image. Thereservoir 53, which may be agitated by known means, replenishes thesupply of developer powder to the developer mix in the trough 45.

The copy sheet is next carried past the fusing station 55 wherein thesurface of the copy sheet is heated to soften thermosplastic portions ofthe developer powder or the copy sheet coating to permanently fuse thedeveloper powder to the copy sheet. In this manner, the visible image ismade permanent.

After the trailing edge of the copy sheet has been carried past theexposure station, the lamps 21 may be turned off by the means describedabove. At this time, the dog 119 has been carried to the point where itrides into the dip 123 of the cam 103. When this occurs, the dog isreleased from its engagement with the pin 117 and the subject holder isnot advanced further, having reached its forward position. The drumcontinues to rotate until it reaches its index position wherein the copysheet may then be manually removed by again moving thecontrol finger 141in thedesired direction.

Arnachine, as described :inth'e foregoing specification,

hasbeenconstructed for reproducing original size-copies of'standard andlegal size sheets. The overall dimensions of this machine, with thecover in the closed position, are height 26 inches, width 15 inches anddepth 18 inches. With respect to the small size of the machine, afeature of the'machine is the mounting means forthe subject holderwherein atraverse path for the holder is substantially longer than thedepth dimension of the machine. Another feature ofv the machine is thecoupling mechanism whereby the subject holder is advanced only duringthe desired portion of each-cycleof the copy drum and-whereby themovement of the subject holder is prefectly synchronized with the copydrum so that any irregularities in the drumrotation are accuratelyduplicated'inthe subject'holder; A sharp image is therefore assured,even though a low cost and a not very steady drum drive is used; Afurther feature of the machine is: the drum clamping means wherein acopy sheet may be inserted to two predetermined depths-Which are readilyselective by the operator. Further features are the ease of operationand'the clean appearance of the machine housing, which are desirablefeatures in ofiice equipment.

What is' claimed is:

1. In'acopyin'g machine including a linearly movable subject holder forsupporting a subject to be copied, a-

rotatable copy holder drum, and means for reflecting light-fromsaidsubject to said drum, apparatus comprising: means for cyclicallyimparting rotation to said drum, a rotary member associated in axialalignment with said drum and having a working diameter substantiallyequal to that of said drum, a clutch mechanism associated with said drumand'said rotary member and adapted to couple said rotary member to saiddrum to provide coincident ro-' tation thereof after said drum hasrotated'a first predetermined'distance and adapted to uncouple saidrotary member from said drum after an additional predetermined rotation,a flexible endless member adapted to be driven by said rotary member andhaving a portion thereof coupled to said movable subject holder, saidendless member being thereby adapted to impart linear motion to saidsubject holder and to synchronize the linear speed of said subjectholder with the peripheral speed of said drum. I

2. In a copying machine including a linearly movable subject holder forsupporting subject matter tobe copied, a rotatable copyv holder drum,and means for reflecting light from said subject matter to said drum;apparatus comprising: means for cyclically driving said drum, a rotarymember axially aligned with and adjacent to said drum and freelyrotatable with respect to saiddrum, latch means mounted on said drumbetween said drum and said rotary member, latch engaging means mountedon said rotary member, said latch means and said engaging means being sopositioned as to engage one with the other a predetermined time afterinitiation of a drum rotation cycle, and a stationary cam member mountedbetween said drum-and said rotary member adapted to disengage said latchmeans from said latch engagingmeans after a predetermined coincidentrotation of said drum and said rotary member, a flexible endless memberadapted to be driven by said rotary member and having a portion thereofcoupled to said movable subject holder, said endless member beingthereby adapted to impart linear motion to said subject holder and tosynchronize the linear speed of.- said subject holder with theperipheral speed of said'drum;

3. In a copying machine-including a linearly movable subject holder forsupporting subject matter to be copied, a rotatable copy holder drum,and means for reflecting light from saidsubject matter to said drum;apparatus comprising: a first pulley on said drum for cyclicallyapplying rotational motion thereto, a second pulley adjacent to and inaxial alignment with said drum and said first pulley, said secondpulleybeing mounted to rotate independently of said first pulley and having aworking diameter substantially equal to the working diameter of saiddrum, an'endless cable coupling said second pulley to said subjectholder, a portion of said cable defining a linear path parallel to saidsubject holder, latch means mounted on said first pulley, latch engagingmeans mounted on said second-pulley, said latch means and said latchengaging means being so positioned as to engage one with the other apredetermined time after initiation of a drum'rotation cycle, and astationary cam member. mounted betweensaid pulleys adaptedto dis engagesaid latch means from said-latch engaging means after a predeterminedcoincident rotation of said pulleys.

4. Ina copying machine including a linearly movable subject holderforsupportingsubject matter to be copied, a rotatable copy holder drum,and means for reflecting light from said subject matter to said drum;apparatus comprising: a first pulley on said drum for cyclicallyapplying rotational motion thereto, a second pulley adjacent to and inaxial alignment with said drum and said first pulley, said second pulleybeing mounted to rotate independently of said first pulley and having aworking diameter substantially equal to that of said drum, an endlesscable coupling said second pulley to said subject holder, a portion ofsaid cable defining a linear path parallel to said subject holder, a pinmounted on said second pulley and extending toward said first pulley, acam follower mounted on said first pulley and adapted to engage saidpin, said cam follower and said pin being so positioned as to engage onewith the other a predeterminedtime after initiation of a drum rotationcycle, and a stationary cam mounted between said pulleys adapted todisengage said cam follower from said pin after a predeterminedcoincident rotation of said pulleys.

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